CN109971359B

CN109971359B - Chemical mechanical polishing solution

Info

Publication number: CN109971359B
Application number: CN201711439628.1A
Authority: CN
Inventors: 周文婷; 荆建芬
Original assignee: Anji Microelectronics Shanghai Co Ltd
Current assignee: Ningbo Anji Microelectronics Technology Co ltd
Priority date: 2017-12-27
Filing date: 2017-12-27
Publication date: 2021-12-07
Anticipated expiration: 2037-12-27
Also published as: CN109971359A; TWI797223B; WO2019129102A1; TW201927952A

Abstract

The invention provides a chemical mechanical polishing solution, which comprises silicon dioxide, at least one accelerating agent, azole compounds and derivatives thereof. The invention greatly improves the SiN polishing speed, has lower TEOS polishing speed, simultaneously realizes the reduction of the copper polishing speed, and can repair the disc-shaped recess on the mixed bonding surface in a shorter time.

Description

Chemical mechanical polishing solution

Technical Field

The invention relates to the technical field of chemical mechanical polishing solution, in particular to chemical mechanical polishing solution with high silicon nitride, low silicon dioxide and low copper removal rate.

Background

The three-dimensional integrated circuit needs to realize the internal interconnection of thousands of chips while bonding two wafers, and these need to carry out conductive bonding on the two wafers, generally, the conductive connection can be realized by a simple metal bonding process and a hybrid bonding process (hybrid bonding) with higher bonding strength, and because the strength which can be achieved by the simple metal bonding process is not ideal, the hybrid bonding process is the first choice of the bonding process in the current three-dimensional integrated circuit.

The hybrid bonding technology is a bonding process in which metal and insulator are simultaneously arranged on bonding interfaces of wafers, and in the bonding process, the metal and the metal on the bonding interfaces of the two wafers are aligned, the insulator and the insulator are aligned, and bonding is performed under a certain temperature condition. Typically, the insulator at the bonding interface is silicon dioxide or silicon nitride, and the metal is copper. The common bonding process is to form a layer of silicon nitride on the surface of a wafer, then form a layer of silicon dioxide film on the surface of the silicon nitride, form a trench by photolithography and etching, fill and deposit metal in the trench by a metal deposition method and cover the surface of the film, and then remove the copper and the silicon dioxide film on the surface by a CMP step to obtain an interface layer of silicon nitride and copper. The mixed bonding surface has both metal and insulating substances, and the requirement on the flatness of the bonding interface surface is very high. The grinding liquid with high silicon dioxide and low silicon nitride removal rate is used for removing the silicon dioxide film, and meanwhile, a large disc-shaped recess is formed, and the surface flatness is greatly reduced. In order to reduce such defects, it is desirable to provide a slurry that repairs the surface with a high silicon nitride, low silicon dioxide, low copper removal rate, and results in a surface with a higher degree of planarity in a shorter period of time.

Disclosure of Invention

In order to solve the problems, the invention provides a chemical mechanical polishing solution, which is characterized in that a pyridine compound, a piperidine compound, a pyrrolidine compound or a pyrrole compound containing one or more carboxyl groups is added, the pH value of the polishing solution is adjusted to be 1.5 units and less than 6 of the pKa1 of the compound, the polishing speed of SiN is greatly improved, the lower TEOS polishing speed is realized, meanwhile, the polishing speed of copper is reduced by using an azole compound, and the dishing on a mixed bonding surface can be repaired in a shorter time.

The invention provides a chemical mechanical polishing solution, which comprises silicon dioxide, at least one accelerating agent, azole compounds and derivatives thereof. The speed increasing agent is one or more of pyridine compounds, piperidine compounds, pyrrolidine compounds or pyrrole compounds containing one or more carboxyl groups and derivatives thereof.

Preferably, the mass percentage concentration of the silicon dioxide is 0.5-8%, more preferably 1-5%.

Preferably, the speed increasing agent is selected from 2-carboxypyridine, 3-carboxypyridine, 4-carboxypyridine, 2, 3-dicarboxylpyridine, 2, 4-dicarboxylpyridine, 2, 6-carboxypyridine, 3, 5-dicarboxylpyridine, 2-carboxypiperidine, 3-carboxypiperidine, 4-carboxypiperidine, 2, 3-dicarboxylpiperidine, 2, 4-dicarboxylpiperidine, 2, 6-dicarboxylpiperidine, 3, 5-dicarboxylpiperidine, 2-carboxypyrrolidine, 3-carboxypyrrolidine, 2, 4-dicarboxylpyrrolidine, 2, 5-dicarboxylpyrrolidine, 2-carboxypyrrole, 3-carboxypyrrole, 2, 5-dicarboxylpyrrole, 3, 4-dicarboxylpyridine.

Preferably, the mass percentage concentration of the speed accelerator is 0.001-1%, more preferably 0.01-0.5%.

Preferably, the azole compounds and derivatives thereof include 1,2, 3-triazole, 1H-tetrazole, 1,2, 4-triazole, 1-methyl-5-aminotetrazole, 5-methyltetrazole, 1-amino-5-mercapto-1, 2, 4-tetrazole, 5-phenyltetrazole and 1-phenyl-5-mercapto tetrazole, benzotriazole, 5-methyl-1, 2, 3-benzotriazole, 5-carboxybenzotriazole, 1-hydroxy-benzotriazole, 3-amino-1, 2, 4-triazole, 3, 5-diamino-1, 2, 4-triazole, 5-carboxy-3-amino-1, 2, 4-triazole, 1-hydroxy-benzotriazole, 1,2, 4-triazole, 1,2, 4-triazole, 5-carboxy-3-amino-1, 4-triazole, 1,2, 4-triazole, or their derivatives, 3-amino-5-mercapto-1, 2, 4-triazole, 5-acetic acid-1H-tetrazole, 5-methyltetrazole and 5-amino-1H-tetrazole.

Preferably, the azole compound and the derivative thereof are present in a concentration of 0.001 to 3% by mass, more preferably 0.01 to 1% by mass.

Preferably, the pH of the chemical mechanical polishing solution is greater than 1.5 units and less than 6.5 of the pKa1 of the pyridine compound, piperidine compound, pyrrolidine compound, or pyrrole compound having one or more carboxyl groups.

Preferably, the chemical mechanical polishing solution further contains a bactericide. More preferably, the bactericide comprises one or more of 5-chloro-2-methyl-4-isothiazolin-3-one (CIT), 2-methyl-4-isothiazolin-one (MIT), 1, 2-phenylpropylisothiazolinone (BIT), iodopropynyl carbamate (IPBC), 1, 3-dimethylol-5, 5-methylhydantoin (DMDMH).

Preferably, the chemical mechanical polishing solution further comprises a pH regulator selected from HNO₃、KOH、K₂HPO₄Or KH₂PO₄。

Compared with the prior art, the invention has the technical advantages that:

1) one or more of a pyridine compound, a piperidine compound, a pyrrolidine compound or a pyrrole compound having one or more carboxyl groups, exhibits a high SiN polishing rate and a low TEOS polishing rate at a pH of the polishing slurry of more than 1.5 units and less than 6 of the above-mentioned component Pka1, and has a high SiN/TEOS selectivity ratio;

2) azole compounds and derivatives thereof are added into the polishing solution, so that the polishing speed of copper is low, and the disc-shaped depression on the mixed bonding surface can be repaired in a short time;

3) the chemical mechanical polishing solution can be prepared into a concentrated sample for use, and the cost is reduced.

Detailed Description

The advantages of the present invention will be described in detail below with reference to comparative examples and examples consistent with the present invention.

According to the formulation given in table 1, all the components were dissolved and mixed uniformly, water was used to make up the mass percentage to 100%, and then pH was adjusted to a desired value with a pH adjuster to obtain comparative examples and examples as described in table 1.

Then the specific polishing conditions are as follows: mirra machine, IC1010pad, speed 93/87; polishing pressure: 3.0 psi; polishing 8 inches of silicon nitride, silicon dioxide and copper for 1min at a polishing flow rate of 150ml/min, and then cleaning, drying and detecting to obtain the polishing results shown in the table 1. Then, for the bonded wafer from which the silicon oxide film had been removed, concave defect repair was performed with the polishing liquid in table 1 for a polishing time of 15 seconds, and the dishing value before wafer repair was 120A, wherein the dishing repair results of the comparative example and the inventive example are shown in table 1.

TABLE 1 formulation and polishing effect of comparative examples and examples

As can be seen from the results of comparative examples 1 and 2, the addition of only a pyridine compound, a piperidine compound, a pyrrolidine compound or a pyrrole compound having a carboxyl group to the polishing composition increased the polishing rate of silicon nitride and decreased the polishing rate of silicon dioxide without changing the polishing rate of copper.

As can be seen from the polishing results of comparative example 2, in comparative example 2 in which no azole compound was contained, the polishing liquid exhibited a high copper polishing rate and a low silicon nitride polishing rate, and dishing on the wafer surface was not repaired but became larger, and it was seen that the high copper polishing rate and the low silicon nitride polishing rate were disadvantageous for the repair of dishing.

However, it can be seen from the results of the examples of the present invention that the addition of the compound containing a carboxyl group to the polishing solution increases the polishing rate of silicon nitride and decreases the polishing rate of silicon dioxide, and the addition of an appropriate amount of the azole compound decreases the polishing rate of copper, so that the selectivity of silicon nitride to silicon dioxide and the selectivity of silicon nitride to copper are greatly increased, and thus the butterfly-shaped recess can be repaired within a short time during the polishing process, and the butterfly-shaped recess is decreased to below 30A. According to the invention, by utilizing the compounding effect of the carboxyl group compound and the azole compound, the obtained polishing solution has high silicon nitride speed and low polishing speed of silicon dioxide and copper, the disc-shaped recess of the bonded wafer is repaired, and the surface of the wafer with higher flatness can be obtained.

It should be noted that the embodiments of the present invention have been described in terms of preferred embodiments, and not by way of limitation, and that those skilled in the art can make modifications and variations of the embodiments described above without departing from the spirit of the invention.

Claims

1. The chemical mechanical polishing solution is characterized by comprising silicon dioxide, at least one speed accelerator, azole compounds, a pH regulator and water; wherein the speed-increasing agent is a pyridine compound, a piperidine compound, a pyrrolidine compound or a pyrrole compound containing one or more carboxyl groups, wherein the speed-increasing agent is selected from 2-carboxypyridine, 3-carboxypyridine, 4-carboxypyridine, 2, 3-dicarboxylpyridine, 2, 4-dicarboxylpyridine, 2, 6-dicarboxylpyridine, 3, 5-dicarboxylpyridine, 2-carboxypiperidine, 3-carboxypiperidine, 4-carboxypiperidine, 2, 3-dicarboxylpiperidine, 2, 4-dicarboxylpiperidine, 2, 6-dicarboxylpiperidine, 3, 5-dicarboxylpiperidine, 2-carboxypyrrolidine, 3-carboxypyrrolidine, 2, 4-dicarboxylpyrrolidine, 2, 5-dicarboxylpyrrolidine, 2-carboxypyrrolidine, one or more of 3-carboxypyrrole, 2, 5-dicarboxylpyrrole and 3, 4-dicarboxylpyridine; the azole compounds comprise 1,2, 3-triazole, 1H-tetrazole, 1,2, 4-triazole, 1-methyl-5-aminotetrazole, 5-methyl tetrazole, 1-amino-5-mercapto-1, 2,4 tetrazole, 5-phenyltetrazole and 1-phenyl-5-mercapto tetrazole, benzotriazole, 5-methyl-1, 2, 3-benzotriazole, 5-carboxyl benzotriazole, 1-hydroxy-benzotriazole, 3-amino-1, 2, 4-triazole, 3, 5-diamino-1, 2, 4-triazole, 5-carboxyl-3-amino-1, 2, 4-triazole and 3-amino-5-mercapto-1, one or more of 2, 4-triazole, 5-acetic acid-1H-tetrazole, 5-methyltetrazole and 5-amino-1H-tetrazole; the mass percentage concentration of the silicon dioxide is 0.5-8%; the mass percentage concentration of the speed increasing agent is 0.001-1%; the mass percentage concentration of the azole compound is 0.001-3%; and the pH of the chemical mechanical polishing solution is greater than 1.5 units and less than 6.5 of the pKa1 of the pyridine compound, piperidine compound, pyrrolidine compound, or pyrrole compound having one or more carboxyl groups.

2. The chemical mechanical polishing solution according to claim 1, wherein the concentration of silicon dioxide is 1% to 5% by mass.

3. The chemical mechanical polishing solution according to claim 1, wherein the mass percentage concentration of the accelerator is 0.01 to 0.5%.

4. The chemical mechanical polishing solution according to claim 1, wherein the azole compound is present in a concentration of 0.01 to 1% by mass.